Implantable surgical meshes have been widely used for a variety of different surgical procedures such as hernia repair, pelvic floor repair, urethral slings for treating fecal and urinary incontinence, and many others.
For example, urinary incontinence is a disorder that generally affects women of all ages. The inability to control urination can impact a subject both physiologically and psychologically. Urinary incontinence can interfere with a subject's daily activity and impair quality of life. Stress urinary incontinence is one type of urinary incontinence. Actions including straining, coughing, and heavy lifting can cause women with stress urinary incontinence to void urine involuntarily.
Various physiological conditions cause urinary incontinence in women. Stress urinary incontinence is generally caused by two conditions that occur independently or in combination. One condition, known as intrinsic sphincter deficiency (ISD), occurs when the urethral sphincter fails to coapt properly. ISD may cause urine to leak out of the urethra during stressful actions. A second condition, known as hypermobility, occurs when the pelvic floor is weakened or damaged and causes the bladder neck and proximal urethra to rotate and descend in response to increases in intra-abdominal pressure. When intra-abdominal pressure increases due to strain resulting from coughing, for example, urine leakage often results.
One method for treating stress urinary incontinence includes placing a sling to either compress the urethral sphincter or placing a sling to provide a “back stop” to the bladder neck and proximal urethra. Providing support to the bladder neck and proximal urethra maintains the urethra in the normal anatomical position, while elevation places the urethra above the normal anatomical position.
Other pelvic tissue disorders include cystocele, rectocele, enterocele, and prolapse such as vaginal vault prolapse. Pelvic disorders such as these can result from weakness or damage to normal pelvic support systems. Due to the lack of support, structures such as the uterus, bladder, urethra, small intestine, or vagina, may begin to fall out of their normal positions. Conditions referred to as “conditions of the pelvic floor” include conditions caused by weakness or injury to pelvic floor muscles, including levator muscles.
A cystocele is a medical condition that occurs when the tough fibrous wall between a woman's bladder and vagina (the pubocervical fascia) is weakened, such as by tearing, allowing the bladder to herniate into the vagina. A rectocele is a bulge of the front wall of the rectum into the vagina. The rectal wall may become thinned and weak, and it may balloon out into the vagina with pressure coming from the bowel. Enterocele is a hernia of the lining of the peritoneal cavity with or without abdominal viscera. The enterocele can occur posteriorly with or without inversion of the vagina.
Certain types of pelvic floor repair procedures, for example, can involve transvaginal access to internal tissue through a relatively small incision. Procedures can involve the transvaginal insertion of a support member, such as a mesh sling or implant, for supporting specific tissue. The support member may include a central tissue support portion positioned at tissue of a vaginal vault, and extension portions that are moved through respective tissue pathways and their ends anchored at target anatomical sites.
In a transvaginal procedure, portions of the implant are in contact with or pass through vaginal mucosal tissue, which is a unique anatomical area of the body and that presents some challenges for surgical procedures involving implanted meshes. The vaginal mucosa is lined by squamous epithelium without any glands, and the subepithelial layer contains the vaginal blood vessels. Vaginal secretions contain vaginal epithelial cells and Doderlein's bacilli. Doderlein's bacillus is a commensal species that lives in the vagina, and the bacillus metabolizes glycogen in the vaginal epithelial cells, producing lactic acid. This reduces the vaginal pH to around 5.0 with is too low for many other species including pathogens. Epithelial cells and bacillus that may become attached to the implant during or after the transvaginal procedure are of concerns following surgical implantation/fixation. For example, epithelialization of implant surfaces can prevent desirable tissue in-growth and healing around the mesh.
Accordingly, there is need for improved implantable surgical meshes that reduce or alleviate the problems associated with the treatment of female pelvic conditions.